Ukrainian Military Warns Ships Against Heading to Russian Black Sea Ports

Warnings by both Russia and Ukraine to strike cargo ships in the Black Sea are escalating a dispute over grain shipments and threatening to broaden the war to the strategic waterway.

Ukraine’s declaration, which takes effect midnight Thursday, said all ships sailing to Russian-controlled ports would be doing so “with all associated risks.” In addition, sailing in the northeastern Black Sea and the Kerch Strait separating occupied Crimea from Russia was “prohibited by Ukraine as dangerous,” starting at 5 a.m. Thursday, the Ukrainian Defense Ministry said.

Russia issued a similar threat Wednesday, saying it would consider any vessels heading to Ukraine’s Black Sea ports to potentially be carrying military supplies, and sought to ban ships from plying some areas that are in international waters.

“The Russian Federation has once again brutally violated the universal right to free navigation for the whole world and is deliberately undermining food security, condemning millions of people to starvation,” the Ukrainian Defense Ministry said.

The warnings deepen the uncertainty around Black Sea shipping days after Russia withdrew from the Black Sea grain agreement that allowed Ukraine to resume much of its food exports last year, including to markets in the Middle East and Africa, where food supplies have been a persistent concern since the war began. In the hours after Moscow pulled out, its forces began hammering the port of Odesa with air barrages that Ukrainian military officials said were specifically targeting essential infrastructure there.

White House spokeswoman Olivia Dalton said Thursday that the U.S. government has “seen indications that [the Russians] are essentially preparing” for potential attacks on civilian vessels carrying grain through the Black Sea.

National Security Council spokesman John Kirby said the latest U.S. intelligence estimates also suggest that Russia is considering placing additional sea mines in the approaches to Ukrainian ports—setting up a potential false flag operation. “We believe that this is rather a coordinated effort to justify any attacks against civilian ships in the Black Sea and to then blame them on Ukraine,” Kirby told reporters. 

Russia’s February 2022 invasion initially brought Ukraine’s Black Sea exports to a halt, imposing a de facto blockade on the country’s ports, which had been responsible for 95% of the country’s agricultural exports before the war. Exports from the country’s major Black Sea ports have again plunged since Russia withdrew from the grain deal this week.

Now, Ukraine is attempting to restrict traffic to Russia’s Black Sea ports, choking Moscow’s own exports, much as Russia has tried to deny access to Ukraine’s ports.

“With its current conduct, tearing up the deal and strikes on Odesa port infrastructure, it is showing that it’s trying to dominate in the Black Sea,” said Mykhailo Podolyak, an adviser to Ukrainian President Volodymyr Zelensky, referring to Russia.

He said Ukraine’s warning is aimed at showing that if Russia violates international law, Ukraine should have a right to strike back, even using Western-supplied weapons against targets on Russian territory—something it is now restricted from doing.

“This is not a mirror response,” Podolyak said in an interview, adding that the air defenses around Odesa have struggled to intercept Russian missiles.

Military analysts say Ukraine is unlikely to actually strike Russian cargo ships because it has only a limited supply of anti-ship missiles. It also faces constraints on its ability to gather targeting data beyond the areas it controls.

Still, the Ukrainian ultimatum could block some shipping to and from Russia by causing insurance companies to stop covering ships heading to the area.

“What’s happening here is that the Ukrainians are attempting to turn the tables on the Russians by imposing an insurance blockade on them,” said Michael Petersen, the director of the Russia Maritime Studies Institute at the U.S. Naval War College.

Since being hit with Western sanctions after invading Ukraine, Russia has turned to a shadow fleet of aging tankers and other ships to keep its oil exports moving. Its Black Sea ports are increasingly important to its economy, shipping grain, oil and other commodities. The port of Novorossiysk alone accounts for 17% of Russian maritime trade.

Ukraine has used its Harpoon and Neptune antiship missiles, along with armed drones, to sink Russian warships and push the Russian navy back from the waters around the city of Odesa. Russia has turned to its fleet of civilian cargo ships to transport weapons during the war, The Wall Street Journal has previously reported.

Ukraine has also used maritime drones to devastating effect. On Monday, explosions disabled the bridge linking Russia to the occupied Crimean Peninsula in an attack widely thought to have been carried out by Ukraine.

“I’m just not convinced the Ukrainians have enough wherewithal to impose some kind of strict blockade on Russian ships. There’s too many cargo vessels. The Russians have too many security measures and the Ukrainians have too few resources at sea,” said Petersen.

Russia has long sought to expand its power in the Black Sea region, drawing on memories of its imperial past, when it first stationed the headquarters of its Black Sea fleet in Sevastopol, Crimea in 1783. Russia occupied and annexed Crimea in 2014 when it began its low-level war in southern and eastern Ukraine.

Since the 2022 invasion, Ukraine’s southern coastline, including its Black Sea ports, has been a strategic target for Russia, which failed to capture Odesa and other major cities after Ukrainian forces pushed the Russian military back from the city of Mykolaiv.

Ukraine has also thwarted Russia’s attempts to dominate the waterway, sinking the flagship of the Russian Black Sea fleet last year along with several other Russian vessels. Ukraine forces also drove Russian forces off the small but strategic Snake Island in June 2022.

Russia and Ukraine signed the Black Sea Grain Initiative, an agreement brokered by Turkey and the United Nations, in July last year. The deal allowed Ukraine to export more than 32 million tons of corn, wheat, sunflower oil and other goods. The agreement included security guarantees for both countries, with all ships involved in the deal undergoing inspections as they passed in and out of the Black Sea at Istanbul.

Russia suspended its involvement in the deal on Monday saying it wanted the U.N. to honor a separate agreement signed last year that called for lowering barriers to its own food and fertilizer exports.

Ukraine has called for a partnership with Turkey and the U.N. that would keep the Black Sea grain deal going without Russia’s involvement. Its officials say Russia’s threats to shipping in the region came in response to Ukraine’s efforts to find a possible workaround that would allow grain shipments to continue.

Podolyak, the adviser to the Ukrainian president, said Ukraine is mounting a diplomatic effort to continue the grain exports and that its discussions with Turkey and the U.N. involve finding alternative routes, among other options. He said Kyiv also is pushing for convoys protected by Western warships equipped with suitable air defenses—ships such as corvettes or destroyers—to allow grain shipments to continue.

—Annie Linskey in Washington contributed to this article.

Write to Jared Malsin at [email protected]